Inhibition of group B arbovirus antigen production and replication in cells enucleated with cytochalasin B.

A comparative study of the growth of Sindbis (SIN) virus, a group A arbovirus (togavirus), and Japanese encephalitis (JE) virus, a representative group B arbovirus (togavirus), was conducted in enucleate and nucleate cells. Immunofluorescent tests and yield measurements demonstrated that chicken embryo cells which had been enucleated and subsequently infected with SIN virus produced virus-specific antigens and infectious virus. By contrast, JE failed to replicate or produce virus-specific antigen in cells which had been enucleated before or even 2 h post infection. Studies of the effect of enulceation at various times after infection demonstrated that a nucleus must be present at least 2 and possibly as long as 4 h after infection to produce either JE-specific antigen or infectious JE virus. These studies demonstrate that the replication of SIN, a group A arbovirus (togavirus), which has no nuclear requirement, contrasts sharply with that of a group B arbovirus (togavirus), JE, which may have an initial dependence on a nucleus-associated process.